You're paying for a guaranteed spot. In my contract, I tell parents they are paying based on enrollment, not attendance. Does your dc charge you for closures such as holidays, vacations, days they're closed due to illness, etc.? This is paying based on enrollment, not attendance. If your contract states that, then your options are to pay and move forward, or find other dc that does not charge based on enrollment but attendance only.
I'm sorry for the destruction Irma brought to your state and many other places. Sad and devastating indeed.
And it may seem heartless to get charged for dc during such a catastrophe but if you've never had any issues before and you've always appreciated, respected and loved the care your child has gotten, then maybe you should try and show those feelings by making sure they get paid. If you don't respect the care they give, don't appreciate anything they've done in caring for their child, then it's best to pull out and find someone else. But if you did indeed sign a contract such as was mentioned above, then you really have no leg to stand on as to it being illegal.